In a moving vehicle such as an automobile, agricultural machine or watercraft, remote monitoring systems are known to monitor such parameters as the engine operating conditions and position information. An outboard engine unit used in a watercraft, in particular, has to operate continuously for long periods of time under harsh conditions. A demand has accordingly existed for maintenance conditions as well as the operating status to be monitored remotely.
Therefore, a technology is known in which a mobile telephone is housed in an outboard engine unit secured to the stern of a watercraft, a remote set is connected inside the cabin to operate the mobile telephone remotely, and maintenance and communication are performed externally by operating the remote set. This technology has been disclosed, for example, in Japanese Patent Application Laid-Open Publication No. 2004-228773 (JP 2004-228773 A).
However, the technology disclosed in JP 2004-228773 A is not suitable for use at sea where there are no base stations when underway. In this situation, remote monitoring related to operating and maintenance conditions cannot be performed wirelessly. Also, when this technology is used in various countries around the world, there are areas in which communication cannot be conducted using the available communication protocols. Therefore, remote monitoring similar to the case described above cannot be performed. As a result, there is a demand for reliable and stable onboard monitoring of an outboard engine unit.